No, there is really no such thing as a "global toll free number."  While UIFN numbers aren't really global toll free numbers;  they can be dialed from multiple countries. There are quite a few rules and restrictions that come with UIFN numbers:

• A UIFN number must be registered in at least two countries.
• A UIFN number must be in service for two or more countries 180 days from the day that your business reserved it.

If your business wants to use one number (that is free to call for customers) in multiple countries, a UIFN number is often a viable choice. But, be sure to check with your provider on coverage and restrictions before you sign any contracts. UIFN numbers are expensive, and they come with a hefty setup fees.